Koroit Opal Field

Koriot is situated 100 kilometres north west of Cunnamulla on the Humeburn Road. However, unlike Yowah, it does not cater to fossicking.

Opal was first discovered there in 1902 and testing began in May 1903.

The following snapshot is an excerpt from:
BEAUTIFUL YOWAH - Black Gate & Koroit
Published & Distributed by Len Cram
PO Box 2
Lightning Ridge
NSW 2834
Phone: (02)6829 0527
ISBN 0 64626007 3 1995

The field was first worked by a private Glasgow syndicate known as the "Scottish Australian Opal Company".

They originally prospected the area with drills, shafts and tunnels. For their day it was quite scientific. They were looking not only for the beds of nuts and boulders; but the channels and faults in the band at the junction of the sandstone and opal dirt where pipe and free opal formed.

There was on average ten men employed, who by the end of 1904 had completed 150 shafts between 5 and 15 metres, as well as six water shafts with the capacity of 80,000 litres.

From these shafts 472 metres of drives were completed, and 300oz of medium grade and 30oz of fine grade opal was produced.
The selected amount of boulder matrix was one and a quarter ton.

A considerable amount of propecting was carried out within an eight kilometre radius of the workings, mainly by drilling.

The estimated amount of opal and matrix produced was 2000 pounds. This was at a time when London market was under pressure from an influx of low grade opal, especially from White Cliffs. Because of the depressed prices the company decided to reserve their parcels of opal and closed down operations for a period of time, leaving only a caretaker on the field.

For reasons known only to the syndicate the mines never went into production, even though their chief engineer had designed a successful underground pueumatic digging machine.

By 1906 the field lay dormant. Like the Yowah, Koroit has had a checkered history, but it wasn't until after World War 2 that any strong interest was again taken in the field.

Beautiful Yowah
(Black Gate & Koroit)
ISBN 0 646 26007 3 1995
Written by Len Cram
PO Box 2
Lightning Ridge
NSW 2834
Phone: (02) 6829 0527

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